1. Field of the Invention
The present invention relates to a break pressure controlling device for preventing a slip of a wheel, in particular a pressure controlling device which is constituted integrally by a break pressure actuator and a controlling circuit thereof.
2. Discussion of Background
Conventionally, an anti-skid break, a traction control, a stability control system or the like is proposed as a system of controlling break pressure in a vehicle. These systems include a pressure source for producing the break pressure such as a master cylinder and a motor pump, an actuator for controlling pressure (hereinbelow referred to as H/U) which is provided with respect to wheel cylinders provided respectively in the wheels, various sensors for detecting rotational speeds of the wheels, an operation of accelerator pedal, acceleration of vehicle body and so on, and a control unit (hereinbelow referred to as ECU) for outputting a signal for driving said H/U based on information from these sensors. In this, a break pressure applied by a driver or a break pressure produced in a motor pump is controlled by decompressing, holding or compressing upon operations of H/U in accordance with an instruction from ECU responding to the information of sensor, whereby a slip of a wheel can be prevented; a drivability and a stability of the vehicle are obtainable; or a running posture of the vehicle can be controlled.
Incidentally, H/U was provided in an engine room and ECU was provided in a cabin conventionally in such a system. However, in recent years, a device provided with H/U and ECU integrally in the engine room is proposed.
For example, a conventional device of the anti-skid device disclosed in Japanese Unexamined Patent Publication No. Hei 5-505446 (JP-A-5-505466), wherein the structure as a whole is shown in FIG. 9. In FIG. 9, numeral 1 is a cross-sectional view of ECU having a plurality of electromagnetic coils 3a, 3b and 3c; and numeral 2 designates H/U for controlling break pressure having a plurality of valve units 4a, 4b and 4c, which is schematically shown. ECU and H/U are engaged to each other and equipped in a vehicle as an integral object. Meanwhile, the valve units 4a through 4c are built in domes 5a through 5c. The domes 5a through 5c are inserted in a central holes of the coils 3a through 3c and located in a predetermined position. Further, these coils are held by a supporting member 31 through an elastic holding member 30 so as to be movable. Numeral 8 designates an electronical circuit portion connected to a connector 10 for enabling connection to the outside and electrically connected to the coils 3a through 3c for supplying an electric power.
In such a device having an electrical part and a mechanical part which are provided separately and integrated when it is finished as a final product, it is important to transmit an electric current applied to the coils effectively to the valve units and to simplify the integration and the separation. Accordingly, in this conventional device, positions of the valve units and the coils are determined such that the coils 3a through 3c can play using the elastic holding members 30 (springs in this example) to facilitate insertion of the domes 5a through 5c and the coils are pressed to contact H/U 2 after the insertion. The electronic circuit portion 8 outputs signals for driving the electromagnetic coils 3a through 3c respectively, in response to an information of wheel speed detected by a wheel speed sensor (not shown). By these driving signals, the coils are applied with a electric current to thereby operate the valve units 4a through 4c for decompressing, holding or compressing the break pressure, whereby an anti-skid control is performed.
Further, in Japanese Unexamined Patent Publication No. Hei 6-298059 (JP-A-6-298059), a conventional device is disclosed, which is shown in FIG. 10. In FIG. 10, the same numerals as those in FIG. 9 designate the same or the similar portions. Because H/U is substantially the same as that described in the above, only ECU is shown. Coils 3a through 3c are embedded in a component 32 having a play from the outer periphery of the coils, and this constitutional portion 32 is fixed to a supporting member 31. Numeral 33 designates a spring which works to press the coils 3a through 3c such that the coils are in contact with H/U 2. When ECU 1 having such a structure is engaged in H/U 2, domes 5a through 5c having built-in valve units 4a through 4c are inserted in holes of the coils 3a through 3c; and the coils work to push an assembling face of H/U 2 by the spring 33, whereby relationship between positions of the domes and positions of the coils are determined as described in the above. Further, the coils 3a through 3c can play in the component 32 to facilitate the engagement.
Incidentally, in both of the conventional techniques, it was necessary to proof against water since the electronic circuit portion 8 is built in the devices.
In the conventional devices, a portion 28 for connecting the coil and the electronic circuit portion had a structure of receiving a stress when ECU and H/U were integrally engaged. The electric connecting portion was applied with this stress, suffered deterioration with age and/or applied with a thermal stress, whereby there was a possibility of breakage at the worst.
Also, there were many small apertures for penetrating the coil terminals in the electronic circuit chamber, whereby it was difficult to proof the electronic circuit chamber against water.
Also, when ECU was assembled, it was necessary to insert the coil terminals into a predetermined small aperture for electrically connecting these, wherein there was a problem that capability of assembling was insufficient.